A method for supplying gaseous fuel from a liquid state to an internal combustion engine includes employing a second internal combustion engine as a source of energy, pumping the gaseous fuel in the liquid state by transforming energy from the source of energy into mechanical work for the pumping, exchanging waste heat from the second internal combustion engine in a first heat exchange fluid circulating through the second internal combustion engine to a second heat exchange fluid, vaporizing the gaseous fuel pumped from the liquid state with heat from the second heat exchange fluid, and delivering the gaseous fuel vaporized from the liquid state to the internal combustion engine. Pressure of the gaseous fuel delivered to the internal combustion engine is maintained within a predetermined range of tolerance by the pumping.